1. Technical Field
The present invention relates to an image-forming device and a medium edge part judgment method.
2. Background Technology
In image-forming devices that form an image on a medium such as a paper, it is well known to detect an edge part of the medium. For example, Patent document 1 discloses an image-forming device that includes a carriage which moves in a width direction of the medium, a recording head mounted on the carriage, and a paper width detection sensor. In this image-forming device, as a paper width detection sensor, an optical sensor is used to detect existence or non-existence of a medium based on an output in response to the light intensity by detecting the reflection light of the irradiated light. And, while the carriage moves in a main scanning direction, the output from the paper width detection sensor compares with a threshold value, and when the output changes and exceeds the threshold value, the change point is identified as an edge part of the medium.
Japanese Laid-open Patent Publication No. 2009-155013 (Patent Document 1) is an example of the related art.